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At least 55 records · Page 3Linked to original sources
PubMed1989

Thiosemicarbazide used after periodic acid makes methenamine silver staining of renal glomerular basement membranes faster and cleaner.

The periodic acid-methenamine silver staining technique, which is frequently used for demonstrating the renal glomerular basement membrane, requires a high degree of skill, and in some cases it may be difficult to obtain a good result. To overcome such difficulty and inconsistency, we have improved the method by performing methenamine silver staining after oxidation with periodic acid and subsequent application of thiosemicarbazide. In this procedure, this semicarbazide enhanced the reaction of methenamine silver with the glomerular basement membrane and the reaction was completed within a shorter time in comparison with the conventional method. This modification also eliminated any nonspecific reaction with the surface of the glass slide and the solution container and yielded excellent and reproducible results irrespective of the fixation method and material employed. It was also found to stain the renal glomerular basement membrane of rabbits, which is demonstrable only with difficulty by the conventional method.

Animals↗
PubMed1993

Staining senile plaques using Bodian's method modified with methenamine.

A new method is presented for staining various types of senile plaques isolated from the brains of patients with Alzheimer type dementia and related diseases in paraffin embedded sections using a modified Bodian's method with methenamine. This methenamine-Bodian method made it possible to observe diffuse plaques and other amyloid deposits which are barely detected by Bodian's original method. The staining of senile plaques by the method presented here was comparable to that of immunostaining with anti-beta-protein. The new method also stained neurofibrillary tangles. Therefore, the methenamine-Bodian method could be widely used for the detection of senile changes in paraffin embedded sections from autopsied human brains.

Aged↗
PubMed1982

Secondary prevention of recurrent urinary tract infections. Comparison of the effect of placebo, methenamine hippurate, nitrofurantoin and trimethoprim alone.

290 patients with recurrent urinary tract infection were treated with either placebo, methenamine hippurate, nitrofurantoin or trimethoprim. 38.9% of the patients had chronic pyelonephritis and 23.8% azotemia. During the follow-up period of 1 year 63.2% recurred in the placebo group, 34.2% in the methenamine hippurate group, 25.0% in the nitrofurantoin group and 10.4% in the trimethoprim group. 62.5% of the recurrences in the trimethoprim group were associated with trimethoprim-resistant strains. However, such strains appeared only in 6.5% of the patients treated with trimethoprim, compared with 16.2% in the placebo, 8.3% in the nitrofurantoin and 11.0% in the methenamine hippurate groups. Side-effects were mild and occurred most frequently in the nitrofurantoin group (13.9%).

Clinical Trials as Topic↗
PubMed1975

Controlled trial comparing co-trimoxazole and methenamine hippurate in the prevention of recurrent urinary tract infections.

To study the effects of continous low doses of antibacterial agents after eradication of bacteriuria in patients with recurrent urinary tract infection, 31 patients with documented recurrent urinary tract infection were allocated alternately to treatment with either co-trimoxazole (400 mg of suphamethoxazole and 80 mg of trimethoprim each night) or methenamine hippurate (1 g each night). The majority of patients (79%) had underlying radiological abnormalities of the renal tract, but normal renal function (the mean serum creatinine level was 1.05 mg per 100 ml). During the study the incidence of bacteriuria and pyuria was significantly lower in the co-trimoxazole-treated group. Patients receiving co-trimoxazole also had fewer acute clinical episodes of urinary tract infection than patients receiving methenamine hippurate. There were no significant side effects from either drug. Two patients with frequent recurrences of infection developed renal calculi. No change in creatinine clearance or maximum urinary concentrating ability was observed over a follow-up period of four to 30 months (mean 10.4 months). Co-trimoxazole is an effective agent in the prophylaxis of urinary tract infection in this highly susceptible group of patients, and in the doses used was superior to methenamine hippurate.

Adult↗
PubMed1980

Kinetics of hydrolysis of methenamine.

The kinetics of degradation of methenamine were studied in citrate--phosphate buffers between pH 2.0 and 7.4 at 37.5 degrees. GLC was used to monitor the rate of hydrolysis. The conversion of methenamine to formaldehyde was found to be pH dependent in the buffers of constant ionic strength, with the reaction half-life decreasing from 13.8 hr at pH 5.8 to 1.6 hr at pH 2.0. The kinetics of degradation also were measured at 47, 57, and 67 degrees, and the reaction obeyed the Arrhenius relationship. At pH 2.0, the activation energy was calculated to be 23.5 kcal/mole; at pH 5.1, it was 12.0 kcal/mole.

Formaldehyde↗
PubMed1981

In vivo-in vitro correlations with a commercial dissolution simulator. I: Methenamine, nitrofurantoin, and chlorothiazide.

Dissolution profiles were determined for nine methenamine, 14 nitrofurantoin, and six chlorothiazide dosage forms using a dissolution simulator. Various in vivo-in vitro correlations were examined. The best correlation for methenamine was between the maximum urinary excretion rate and the time for 15% dissolution. A good correlation for the 50-mg nitrofurantoin tablets was also found between cumulative percent of drug excreted in 12 hr and the percent dissolved in 1 hr. There were no significant correlations for the 100-mg nitrofurantoin dosage forms. Good correlations were also observed for the 250- and 500-mg chlorothiazide tablets between the percent of drug dissolved in 1 min or the time for 15% dissolution and the maximum excretion rate.

Absorption↗
PubMed1989

Senile plaque-like structures: observation of a probably unknown type of senile plaque by periodic-acid methenamine silver (PAM) electron microscopy.

Numerous diffuse senile plaque-like structures (SPLSs) were found in the cerebral cortex from cases with dementia of the Alzheimer type by means of the methenamine-Bodian method. SPLSs varied in shape and size. They were never recognized in the original Bodian, PAS and Congo red preparations, but were positive with anti-beta-protein immunostaining and periodic-acid methenamine silver (PAM) methods, which are thought to specifically stain amyloid substance. With PAM electron microscopy, we found sparse aggregations of amorphous, often ramified, structures with fine granular silver deposits in SPLS. Routine electron microscopic examination on the same portion where SPLS were confirmed by PAM electron microscopy revealed amorphous, partially fibrous structures. These structures might be amyloid or amyloid-precursor substance. In SPLSs only a few degenerated neurites and astrocytic processes with glycogen granules were seen. We consider SPLSs to be a kind of senile plaque.

Adult↗
PubMed1981

Prevention of recurrent urinary infections in women: a comparative trial between nitrofurantoin and methenamine hippurate.

We treated 99 female patients suffering from recurrent urinary infections with either 1 gm. methenamine hippurate every 12 hours or 50 mg. nitrofurantoin every 12 hours for intervals of up to 1 year. Monthly microbiological and clinical surveillance was done. Both treatments were effective in reducing the incidence of symptomatic attacks, with nitrofurantoin being more effective. The protective effect of prophylaxis continued after treatment had stopped, suggesting that a permanent beneficial action had been produced. Especially during the first month of treatment methenamine hippurate was tolerated better than nitrofurantoin: 28 per cent discontinued therapy with the latter owing to nausea.

Adult↗
PubMed2002

Degeneration of Pick bodies visualized by methenamine-silver staining and immunohistochemistry.

The degeneration process of Pick's bodies (PB) was investigated using methenamine-silver (MS) staining and immunohistochemistry. Methenamine-silver staining sensitively detected extracellular PB as well as intracellular PB in the granular cell layer of the dentate gyrus. Extracellular PB appeared as granular masses with ill-defined boundaries in the neuropil. For MS electron microscopy, the extracellular PB were composed of randomly oriented fibrillary components measuring 9-12 nm in diameter with astroglial processes and degenerated organelles. Tau immunoreactivity of extracellular PB was reduced or abolished. These findings indicate that MS staining is a convenient method for detecting extracellular PB. In addition, it was shown that microglial involvement was associated with PB-bearing neurons at the late stage of the degeneration process and that extracellular PB remained in the neuropil with astroglial reaction.

Aged↗
PubMedDate not supplied

Treatment of hyperhidrosis with topical methenamine.

Idiopathic palmar and plantar hyperhidrosis is a relatively common disorder of eccrine sweat gland function. Treatment with glutaraldehyde of formaldehyde, although successful, may cause undesirable side effects. Methenamine is a polycyclic organic compound which release ammonia and formaldehyde at acid pH. Five per cent methenamine in a firm stick gel, applied daily to one palmar or plantar surface of 109 patients with hyperhidrosis, resulted in significantly less sweating after one month. No patients were sensitized to formaldehyde.

Chemical Phenomena↗
PubMed1980

Lack of effect of ascorbic acid, hippuric acid, and methenamine (urinary formaldehyde) on the copper-reduction glucose test in geriatric patients.

Ascorbic acid and hippuric acid (from cranberry juice) are commonly used to acidify the urine for the purpose of enhancing the degradation of therapeutic methenamine mandelate to urinary formaldehyde. A study was made of 27 nondiabetic geriatric patients with indwelling Foley catheters and chronic bacteriuria who were treated with methenamine mandelate (4 gm), ascorbic acid (4 gm), and cranberry cocktail (1 liter) daily. All of 972 urine samples showed formaldehyde in mean concentrations between 14 and 25 microgram/ml. No glucose was found when the urine was tested by the copper-reduction method. In vitro false positive reactions reported in the literature do not appear to be duplicated as an in vivo problem.

Aged↗
PubMed1978

Long-term prophylaxis with methenamine hippurate in girls with recurrent urinary tract infections.

Twenty girls, aged 5-12 years, with recurrent urinary tract infections, were treated with methenamine hippurate, Hiprex, for a period of 12 months. The number of infections per patient per year was reduced from 3.1 to 0.7 (p less than 0.001). After prophylaxis was stopped this number increased to 1.4 which is a significantly higher incidence than occurred during treatment (p less than 0.05). A few girls complained of the taste but no side-effects were observed. Methenamine hippurate is a useful alternative in long-term prophylaxis against recurrent urinary tract infections in girls.

Child↗
PubMed1974

Generation of formaldehyde from methenamine: effect of pH and concentration, and antibacterial effect.

Using an in vitro system that simulates the dynamics of the urinary tract, we have shown that concentrations of formaldehyde >/= 25 mug/ml can be achieved in urine containing >/= 0.6 mg of methenamine per ml at pH </= 5.7 or >/= 1 mg/ml at pH </= 5.85. Exposure to this concentration of formaldehyde for 2 h produced a measurable antibacterial effect. These studies suggest that an effective bacteriostatic level of formaldehyde is likely to be achieved with currently used dosages of methenamine when the urine pH is less than 5.7 to 5.85.

Anti-Bacterial Agents↗
PubMed1987

Ultrastructural localization of carbohydrates on thin sections of Staphylococcus aureus with silver methenamine and wheat germ agglutinin-gold complex.

Postembedding staining of intracellular carbohydrates on thin sections of Staphylococcus aureus was studied by the silver methenamine and the wheat germ agglutinin-gold techniques. Staining of silver grains was observed on both the cell wall and the cross wall. The staining was interpreted to be due to teichoic acid. Labeling by wheat germ agglutinin-gold particles was observed on both the cell wall and the cross wall, and the staining pattern resembled that of silver methenamine staining. Therefore, the labeling was considered to be due to N-acetylglucosamine of teichoic acid. The combination of two types of cytochemical techniques was useful to localize and characterize the carbohydrates of the bacterial cell.

Carbohydrates↗
PubMed1976

Treatment with methenamine hippurate in the patient with a catheter.

Methenamine hippurate, 1 g twice daily, was given for four months to twenty-two elderly female subjects with an indwelling catheter. The incidence of catheter blockage was significantly reduced when compared with the control period of similar duration, although bacteriuria persisted throughout treatment. The incidence of symptomatic urinary tract infection also decreased during treatment with methenamine hippurate.

Aged↗
PubMed1985

The effects of methenamine-hippurate upon urinary risk factors for renal stone formation.

Among the various treatments for renal calcium stone disease, none has been documented to reduce urinary oxalate. Methenamine-hippurate (Hiprex) has been used extensively in the treatment of urinary tract infections and from micropuncture studies in the rat, using para-aminohippurate, it could be expected to reduce the renal secretion of oxalate. A daily dose of 3 g was given orally to 15 healthy subjects for 2 weeks. However, there was no net decrease in the urinary excretion of oxalate, but a risk index based on the urinary content of calcium, magnesium, oxalate, citrate and urine became reduced during treatment. The urinary inhibition of calcium oxalate crystal growth was unaffected. It is concluded that there may be a potential in methenamine-hippurate for the treatment of calcium stone disease, which can only be evaluated, however, by a clinical trial in stone patients.

Anti-Infective Agents, Urinary↗
PubMed1999

Silver methenamine staining for scanning electron microscopy of bone sections containing biomaterials.

Sections of tissue containing orthopedic materials are currently used to study the compatibility of those materials and to perform electron probe microanalysis at the material-tissue interface. Identification of the cells in contact with the material by Scanning electron microscopy (SEM) is of interest. We have developed a method for staining cells and tissue structures embedded in polymethyl methacrylate with silver methenamine once the sections have been obtained. Sections were prepared by grinding, and the silver methenamine was applied after oxidation with periodic acid. The procedure was carried out in a microwave oven. Backscatter SEM showed staining of the cell nucleus membrane, chromatin, the nuclear organizers, and the chromosomes of dividing cells. The cytoplasm and the cytoplasmic membrane were also stained. Collagen fibers of the extracellular matrix and the mineralized matrix of bone were labeled. Material particles in the macrophages were easily recognizable and Energy-Dispersive Spectrometer were not impaired by the presence of silver in the preparation.

Animals↗